What it means
Flood irrigation is the reason some yards near Camelback Mountain look like Sacramento: lawn to the curb, sixty-year-old grapefruit trees, a canopy of ash and pecan over the street. Every couple of weeks in summer a valve opens at the alley and canal water pours across the yard, held in by a low ridge of dirt called a berm, until it stands ankle-deep and sinks. By morning it is gone and the grass is the color of Ireland.
Locals say “irrigated lot” or “it has irrigation rights” in a real estate listing, and they mean this, not a drip system. The water is raw Salt River and Verde water out of the Arizona Canal, delivered by the Salt River Project, unfiltered and cheap, and the right to it belongs to the land. Sell the house and the right goes with the deed. Let it lapse, and getting it back is a project.
Where you’ll meet it
On the Arcadia streets between 44th and 68th, in the older grid of south Scottsdale south of the canal, in a few 1950s subdivisions near Indian School and Thomas, and in the city parks and school fields that drink the same water. You will also meet it as the alley with a concrete ditch down the middle that nobody seems to own.
Where the word came from
The practice is older than the word. The Hohokam flooded fields from these rivers a thousand years ago, and the farmers who dug the Arizona Canal in the 1880s did the same with more surveying. What made it permanent was the Reclamation Act. In 1903 some 4,800 Valley landowners pledged their acres as collateral for a federal dam on the Salt, the Water Users’ Association was born, and the water rights that came with Roosevelt Dam were tied, by law and by mortgage, to specific pieces of ground. A 1910 court decree sorted which acres had the best rights. Those acres are the “on-project” land, and in Scottsdale they lie south of the Arizona Canal; the north was never pledged and never will be.
Arcadia is the showpiece because it was citrus first. The Arcadia Water Company formed in 1919 to pump canal water uphill to the groves at the foot of Camelback, and by 1924 had laid 15 miles of concrete pipe. The orchards were subdivided for ranch houses from the mid-1950s, lot by lot, and each new owner inherited the grove’s water. The orange trees in Arcadia front yards are the last rows of a farm.
The vocabulary is SRP’s. A zanjero, the ditch rider, opens the headgate and measures the flow. The lateral carries water from the canal to the neighborhood. The neighborhood system, the ditches, pipes and valves past the delivery gate, belongs to the property owners, who are expected to maintain it together.
What it is not
It is not city water and not drinkable. It is not the drip system under your gravel. And it is not “flood irrigation” in the farm sense of inundating a field for days; a residential run is a few inches, gone by morning.
The fine print
SRP delivers to more than 25,000 irrigation customers around the clock, rotating start times so nobody always gets the 3 a.m. slot. A subdivision account gets 18 runs a year on predetermined days, each neighborhood working through an eight-hour rotation; parcels of 1.25 acres and up order water a few days ahead. Once water passes the delivery gate it is the customer’s problem: order only what the yard can hold, keep the berms about twice the height of the water, and accept liability if it escapes into the street or the neighbor’s garage. Annual “dry-ups” for canal maintenance interrupt the schedule each year.
The economics are why it survives. Roughly 20,000 to 22,000 metro properties are irrigated, about 5 percent of SRP’s service lands, and the water costs a fraction of treated city supply because the dams were paid off in 1955 and power sales subsidize the system. Cities use it for parks and ballfields for the same reason. The conservation argument runs both ways: deep, infrequent flooding feeds big trees and flushes salts out of caliche soils, but it also sustains lawns that xeriscape rebates are now paying to remove. In the 1980s, 70 to 90 percent of Phoenix yards were turf; today about 15 percent are.
The failure mode is neglect. In 2019 a Scottsdale neighborhood watch captain complained about a weedy alley on 70th Street. City staff found a neighborhood system serving 68 households of which only 7 still took water, and nobody maintaining the ditch everyone was legally responsible for. The city paid $2,847 for a one-time cleanup and sent letters reminding owners that the alley and the system were theirs. That is the modern condition of flood irrigation south of the canal: a 1903 right, a 1950s pipe and a 2020s HOA-free neighborhood trying to remember who holds the shovel. The Scottsdale Water guide explains where the rest of the city’s water comes from.